frontend: tall videos scale weird

[bacwyls]

Reproduce with this, or another, tall and large mp4 file.

https://openseauserdata.com/files/76b57ebb31cadd11e9bf917fdf8cc613.mp4

The height overflow just breaks the frontend. Navigation is inaccessible, some of chat is out of view.

[bacwyls]

fixed in 9d0fe4e